Draft inducer



March 15, 1938. T. s. HOPKINS 2,111,266

DRAFT INDUCER Fied Dec. 28, 1936 Ilm/*en or. 7720/7705 5. Hop/m5 Patented Mar. 15, 1938 UNITED STATES PATENT ori-lcs DRAFT INDUCER Thomas'S. Hopkins, Los Angeles, Calif. Application December 28, 1936, Serial No. 117,714

1 claims. (01230-95) l This invention relates to a draft inducer which may be used for a large variety of different purposes Where it is desired to induce a draft 'such as, for example, air conditioning equipment, filters, dehumidifiers, driers, gas exhaust apparatusand the-like. A

Anobject of the invention is to provide a draft inducer wherein a tubular member contains a `throat or venturi into which a compressed gas,`

such as compressed air, steam, gas or vapor is to be discharged to induce a flow Vthrough the tubular member, which is particularly silent in .its operation. To this end the tubular member contains a header on which nozzles are mounted directed toward the throat of the venturi, the header and nozzles being shielded by a paraboloidal shield affording on its exterior a stream line flow contributing to the efliciency of the device and on its interior a paraboloidal surface tending to reflect all sounds generated at or near the nozzles through the throat of the venturi so that these sounds will be effectively muffled and dissipated by the volume `of air carried through the throat.

A further object of the invention is to provide a draft inducer which is not only highly eflicient in operation but is of relatively simple and durable construction, adjustments being afforded to enable most efficient operation under a variety of different circumstances.

With the foregoing and other objects in View, which will be made manifest in the following detailed description, and specifically pointed out in the appended claims, reference is had to the accompanying drawing for an illustrative embodiment of the invention, wherein:

Fig. 1 is a sectional View through the improved draft inducer.

Fig. 2 is a sectional view taken substantially upon the line 2 2 upon Fig. 1.

Fig. 3 is a sectional view taken substantially upon the line 3--3 upon Fig. 2.

Fig. 4 is a transverse section taken substantially upon the line 4-4-4 upon Fig. 1.

Referring to the accompanying drawing, wherein similar reference characters designate similar parts throughout, the improved draft inducer comprises a tubular member I0, one end of which may be open to the atmosphere, depending upon the nature of use. It will be understood that the improved draft inducer may be used either as a suction device for exhausting air or gases from a chamber or as a pressure device for building up pressures in large volumes.

Within the tubular member I Il there is disposed a venturi Il having a throat I2. This venturi preferably closely fits the interior of the tubular member and is adjustable longitudinally therein. v It maybe held in any Vadjusted lposition by means of a bolt I3 extending through a slot M in the tubular member.V This bolt is screwed into a nut l5 welded onto the venturi adjacent the throat. By loosening the' bolt the venturi may be adjusted back and forth in the tubular memberlll and locked in adjusted position by tightening the bolt. Within the tubular member there isdisposed a headerl Whichis preferably entirely supported by a supply nipple il extending through an aperture in the tubular member i0. The header and nipple may be formed of a single casting or may be fabricated. Compressed air or gas or other prime mover is designed to be supplied to the header through the nipple from any suitable source of supply. In the preferred form of construction the diam- ,eter of the header is approximately one-half of the diameter of the interior of the tubular member I0. On the rear face of the header there are mounted a plurality of couplings I8 preferably provided with concave hemispherical seats i9 for the balled ends 20 of nozzles or jets 2l. The nozzles or jets 2| are held against the coupling members by bonnets 22, the arrangement being such that on loosening the bonnets the nozzles 2| can be adjusted as to direction. These nozzles are directed toward the throat I2 so that their projected axes converge through the throat.

A paraboloidal shield 23 is arranged on the header on the opposite side thereof from the throat, having its rear end terminating about the outside of the header. It may be mounted thereon in any suitable manner, such as by screws 2li. Its outer or forward surface being paraboloidal in form presents a stream-lined surface reducing friction of flow thereabout and diverting iiow outwardly of the header. The interior of the paraboloidal member 23 being paraboloidal in shape serves to reflect sounds rearwardly through the header and through the throat. This shape materially contributes to the silent or noiseless operation of the improved draft inducer in that sounds generated at or near the nozzles are reflected through the throat and consequently are muied and ldissipated by the air or gas rushing therethrough.

From the above described construction it will be appreciated that the improved draft inducer is of a relatively simple and durable construction and is highly efcient in its operation. Adjustment is provided for the relative distance between the throat and the nozzle and adjustment of the convergence of the nozzles is also provided. 'I'he cone or paraboloidal member 23 not only contributes to stream line flow around the header and nozzles but also is so shaped as to reflect sounds in a direction so as to render the device quiet in operation.

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

l. A draft inducer comprising a tubular member having an inlet and an outlet, means provid' ing a venturi in the tubular member, a paraboloidal member in the tubular member between the inlet and the venturi having its convex side disposed toward the inlet, a plurality of nozzles arranged around the rear edge of the paraboloidal member to discharge toward the throat of the Venturi, the paraboloidal member presenting a concave internal surface which is exposed towardV the venturi inwardly of the nozzles so as to reflect sounds toward the throat of the venturi, and means for conveying fluid to the nozzles to be discharged therethrough.

2. A draft inducer comprising a tubular member having an inlet and an outlet, means providing a venturi in the tubular member, a paraboloidal member in the tubular member between the inlet and the venturi having its convex side disposed toward the inlet, a plurality of nozzles arranged around the rear edge of the paraboloidal member to discharge toward the throat of the venturi, the paraboloidal member presenting a concave internal surface which is exposed toward the venturi inwardly of the nozzles so as to reflect sounds toward the throat of the venturi, and means for conveying fluid to the nozzles to be discharged therethrough, said venturi being adjustable in the tubular member toward and away from the nozzles.

3. A draft inducer comprising a tubular member having an inlet and an outlet, means providing a venturi in the tubular member, a paraboloidal member in the tubular member between the inlet and the venturi having its convex side disposed toward the inlet, a plurality of nozzles arranged around the rear edge of the paraboloidal member to discharge toward the throat of the venturi, the paraboloidal member presenting a concave internal surface which is exposed toward the venturi inwardly of the nozzles so as to reflect sounds toward the throat of the venturi, and means for conveying uid to the nozzles to be discharged therethrough, said nozzles being directionally adjustable.

4. A draft inducer comprising a tubular member having an inlet and an outlet, means providing a venturi in the tubular member, a paraboloidal member in the tubular member between the inlet and the venturi having its convex side disposed toward the inlet, a manifold arranged within the rear edge of the paraboloidal member, nozzles mounted upon the manifold and arranged to discharge toward the throat of the venturi, means for conveying fluid to the manifold to be discharged through the nozzles, said paraboloidal member presenting a concave internal surface exposed through the center of the manifold toward the venturi serving to reflect sounds generated toward the throat of the venturi.

THOMAS S. HOPKINS. 

